1. Field of the Invention
The present invention relates to an engine control unit mounted on an engine and a wire harness for an engine of an automobile, and particularly to a mount position of the engine control unit and rationalization of wiring of the wire harness.
2. Description of the Related Art
Heretofore, ignition timing, fuel injection amount, etc. of an engine in an automobile are controlled in high-level and high-speed, and reliability and durability are required therefor. In response to such a requirement, electronic control is generally used and an engine control unit (hereinafter referred to as xe2x80x9cECUxe2x80x9d) for performing the various kinds of control integrally is employed.
FIG. 4 is a view showing arrangement of components in an engine room of an automobile in the related-art.
Provided in FIG. 4 are a lateral disposed engine 10, an engine room 11, an engine room harness 13, and an engine harness 12.
The engine room harness 13 is divided broadly into a right side harness 13-1, a left side harness 13-2, and a front harness 13-3. The right and left side harnesses 13-1 and 13-2 branch off to be connected to a wiper component 20, a brake component 30, a relay box 40, etc.
Further, the front harness 13-3 branches off so as to be connected to a lamp component 50; a component 60 of a cooling system such as a radiator fan; and a component 65 of an air conditioner system such as a compressor of an air conditioner.
Broadly, the engine harness 12 includes: paths 12-1 and 12-2 wired from an ECU 110 disposed on an assistant seat side in a cabin to engine injectors 100; a path 12-3 connected to a water temperature sensor 80; paths 12-4 and 12-5 branching off from the middle of the path 12-1 so as to be connected to ignition coils 90; and paths 12-6 and 12-7 extended from the paths 12-4 and 12-5 so as to be connected to a battery 120 through a fusible link holder 70.
FIG. 5 is an example of a block diagram of the ECU in the related-art example. The ECU 110 includes electronic components such as a CPU, an ROM, and an RAM, and various circuits. The ECU 110 is supplied with signals from various sensors such as an intake air temperature sensor, and a water temperature sensor, controls and processes these signals, and then outputs these processed signals to a coil, an injector, and so on.
As shown in FIG. 4, the wire harnesses 12-1 and 12-3 make connection between the ECU 110 and the water temperature sensor 80, the wire harnesses 12-1, 12-4 and 12-5 make connection between the ECU 110 and the coils 90, and the wire harnesses 12-1 and 12-2 make connection between the ECU 110 and the injectors 100.
In the related-art, however, the ECU 110 is disposed on the assistant seat side in the cabin, while the injectors 100 and the ignition coils 90 are mounted on the engine 10. Accordingly, it is required to wire a long harness from the ECU 110 in the cabin to the injectors 100 and the ignition coils 90 in the engine room 11. Working area for this wire harness connection is required to extend over two places, that is, in the cabin and the engine room 11. There is therefore a problem in performing such work smoothly.
The invention has been made in consideration of the problem. It is an object of the invention to provide an ECU mounted on the engine body to simplify wiring of a wire harness to thereby make the assembly work smooth and make cost of the components lower.
In order to achieve the object, according to a first configuration, there is provided an engine control unit having electronic components and various circuits for controlling an engine, the engine control unit being mounted on a portion substantially just above an intake manifold of the engine.
According to a second configuration, in the engine control unit defined in the first configuration, an ignition coil circuit and an injector circuit are formed integrally in a case of the engine control unit so that control circuits of a control board are connected to an ignition coil and an injector by slot-in-connectors respectively.
According to a third configuration, in the engine control unit defined in the first or second configuration, a connector for connecting a sensor circuit to the engine control unit and a harness connecting connector are formed on a peripheral wall surface of the case of the engine control unit.
According to a fourth configuration, in the engine control unit defined in any one of the first through third configurations, a fuel flow channel is formed in a lower surface of the case of the engine control unit.